Treatment of prostatic carcinoma by cryosurgery of the primary tumor has, in many cases, resulted in remissions of both primary and metastatic lesions. These results have prompted a great deal of research into possible immunologic mechanisms in the destruction of widely disseminated tumor antigens. The object of the proposed studies is to examine in depth the cellular and humoral immune responses to prostatic tumor antigens in patients following cryosurgery and to correlate the laboratory findings, with post-operative clinical findings. In vivo and in vitro testing will be done before cryosurgery and at various times post-operatively. Pre-operative tests will include skin testing to a variety of standard antigens (tuberculin, histoplasmin, Candida, etc.) to determine the level of immunologic reactivity of each patient; total and differential white blood cell counts and the cellular in vitro reactivity against non-specific mitogens. Serum and blood lymphocytes will be frozen for later testing against specific tumor antigens. Following cryosurgery of the primary tumor nodule, each patient's reactivity to his tumor will be evaluated by a variety of in vivo and in vitro methods. In addition to the clinical studies a more precise examination of the role of the immune response in prostatic cancer will be carried out through the use of a laboratory animal model. Using one of the presently available transplantable prostatic tumors in the rat (both an adenocarcinoma and squamous cell carcinoma are being maintained in our laboratory and an additional adenocarcinoma is expected soon from another laboratory), immunologic analysis of humoral and cellular immunity to tumor antigens will be carried out. More controlled studies will be possible with the animal model as well as the ability to study the underlying cellular mechanisms.